


Never Have I Ever: Cas

by saltandbyrne



Series: Stepbrothers [5]
Category: Supernatural
Genre: Aftercare, Barebacking, Bottom Cas, Comeplay, Consensual Kink, Dom/sub Undertones, Humiliation, M/M, Multi, Shower Sex, Sloppy Seconds, Threesome - M/M/M, Top Dean, Top Sam, Underage - Freeform, Urination, Watersports, weecestiel
Language: English
Status: Completed
Published: 2015-07-29
Updated: 2015-07-29
Packaged: 2018-04-11 23:05:28
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,485
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4455947
Author URL: https://archiveofourown.org/users/saltandbyrne/pseuds/saltandbyrne
Summary: <blockquote class="userstuff">
              <p>“That's it, Sammy,” Dean urges, breathing hot and nasty against Sam's ear. He takes another swallow from his water bottle, slurping noisily around the neck. “Get him nice and dirty for me.”</p>
            </blockquote>





	Never Have I Ever: Cas

**Author's Note:**

> Please read the tags! This is unrepentantly filthy and dirtybadwrong and I'm not even sorry.  
> This story contains watersports (hole pissing and incidental drinking) with Cas the happy recipient of Sam and Dean's attention. If that's not your thing please steer clear!

“What about you, Cas?” Dean propped himself up on an elbow, staring across Sam's chest at Cas' flushed face. His eyes looked bluer around the rims of his pupils, open wide as he blinked.

 

“Yeah, Cas,” Sam turned to his step-brother, letting his head loll against Cas' chest. “Dean wants to wear panties and I want to get DP'd.” Sam smirked at the way Cas swallowed, his adam's apple bobbing in this throat the way it does when he's half-nervous and completely horny.

 

“What about you?”

 

Cas blew a breath out through his lips, swallowing again. He creased his brow in thought and looked down.

 

“C'mon, Cas,” Dean urged, reaching over to run his thumb over Cas' nipple. Cas closed his eyes, licking his lips as Dean lazily played with it.

 

“I want to know the nastiest, filthiest, most fucked-up thing you've ever wanted to try.” Dean's eyes glinted dangerously as he stared at Cas. Sam squirmed between them, feeling his cock stir as Cas bit his lip.

 

“You can tell us anything, Cas, really.” Sam rolled over far enough to press a soft kiss to Cas' neck, feeling Cas' heart skitter against his lips. Dean got off on the way Cas got all nervous and twitchy sometimes, and Sam had come to appreciate it, too. It usually meant Cas wanted to do something really bad.

 

“Well, there's this one thing I saw in a movie...”

 

Dean got his cock in his hand before Cas even finished telling them what he wanted. Sam just groaned and let a smile spread out over his face. Sam was getting straight A's in math, and Cas was a textbook inverse equation of shyness and complete sexual depravity.

 

“I'm down.” Dean arched an eyebrow as Sam nodded his own approval.

 

*

 

Sam can't fucking believe they're doing this.

 

Well, the part where he's nuts-deep in Cas' hot, clenching ass is pretty par for the course at this point. Cas is bent over in front of him, his arms spread lax over the bed, hands clenched in the sheets while Sam pounds into him.

 

“That's it, Sammy,” Dean urges, breathing hot and nasty against Sam's ear. He takes another swallow from his water bottle, slurping noisily around the neck. “Get him nice and dirty for me.”

 

If Cas gets any dirtier he's gonna have jizz coming out of his mouth. This is Sam's third go at him in the past hour, and even Sam's almost-fifteen-year-old nuts are starting to ache. Cas had collapsed into a mumbling mess after the second time, when Sam had slipped into the sloppy-wet remnants of Dean's first orgasm and flipped Cas onto his back. Dean had been extra bossy about that.

 

“Make sure he comes on himself, Sammy,” Dean had barked, arching an eyebrow at the desperate moan Cas had let out. Sam had hiked Cas' legs up to the right angle and stroked him through it, biting his lip to stave himself off until Cas had spilled over his hand and streaked his own chest. He'd come buried as deep he could get, the wet squelch of Dean's come slicking the way while Dean had just drained another bottle of water and smirked.

 

Dean's mouth is cool as he nips along Sam's neck, snaking his finger down to circle over the tight bud of Sam's asshole. Sam takes a moment to feel selfish, frowning as Dean presses teasingly. He kind of wishes he was the one getting fucked within an inch of his life right now. But today is all about taking care of their step-brother, so Sam bucks back far enough to get Dean to slip his finger in before he lets himself tumble over the edge. His hips snap erratically and the bed shakes with each thrust, making the empty water bottles littered in the covers dance.

 

“Come all over his hole, Sammy,” Dean growls, his chest warm against Sam's side as he tugs back on Sam's hips. Sam makes a frustrated huff as he pulls out, loathe to leave the slick-hot tug of Cas' hole but fuck it's worth it. He angles his dick and lands a few good stripes of come across the pink, gaping flutter before him. Dean just groans out a long, “Fuck” that makes all three of them shudder.

 

Cas' hole is wrecked, puffed pink around the edges and stretched wide open. Streaks of come leak down his balls, slicked into tacky rivulets that make his skin shine in the bed side light. His thighs are bright red and sticky with it, and Sam watches a fresh line dribble out while Cas presses his face into the mattress and moans out some nonsense.

 

“Drink your water, Sammy.” Dean hands Sam a fresh bottle and neither of them misses the way the muscles in Cas' back jump. Sam hisses through his teeth and takes a sip, grimacing at the too-full feeling.

 

Sam's gonna piss himself if they don't do this soon.

 

“Dean,” Sam says quietly, shooting a look at his brother. Dean smiles, wicked and wide while Sam's bladder throbs.

 

“S'matter, Sammy?” Dean stage-whispers, leaning down until his lips brush against Cas' ear.

 

“Gotta take a piss?”

 

Cas makes a noise that Sam has never heard, and Sam has seen Cas get fucked on pretty much every surface in a five-mile radius at this point. He looks back at Dean like he's high, eyes barely focused and his lips blushing red.

 

“Fuck,” Dean mutters, apparently as taken aback as Sam is. Cas has something wild in him and it's out in spades as Dean rifles around in the bed. His fingers finally close over the flared black plug.

 

“Get this fucking mess all cleaned up.” Dean slides the plug into Cas' hole, pressing it in with his thumb while Cas arches up for it.

 

“Can't leave that filthy little hole all nasty, can we, Sammy?” Dean slides his hand up the curve of Cas' back and curls his fingers into Cas' hair. Cas groans as Dean pulls his head back.

 

“Get on the floor.” Dean keeps his grip in Cas' hair as he crawls off the bed, clumsy and slow. He clambers to his hands and knees on the floor while Dean waits.

 

Sam steps off the bed and kneels next to Cas, wincing a little at the angle. Fuck, he has to _go_.

 

“We're gonna clean you up so good, Cas,” Sam whispers, pressing a kiss behind Cas' ear before Dean pulls him forward. Cas look pathetic as he slinks after Dean, his come-slick thighs rubbing together, but Sam knows he's loving every second of it. He and Dean are still being way nicer than the guys in the movie Cas had shown them.

 

Dean's bathroom is just across the room, but they walk right past it and into the hall. All three of them could fit into Dean's shower if they had to, but their Dad's is so much bigger.

 

Sam's skin feels too tight as he follows after Dean and Cas. He's sure they feel the same way. None of them have gone to the bathroom for hours, and Sam never thought he'd be so excited just to piss. It's fucked but it sort of makes Sam feel excited, that delirious anticipation spreading out from his throbbing stomach.

 

They stumble into the bathroom, the tile floor cool under Sam's bare feet. Maybe it feels good on Cas' knees or maybe he's just excited, but he starts to whine when Sam opens the door the shower. Sam's knees feel like they're shaking and Dean doesn't look much better.

 

Dean's lips are strained, pressed together thinly as he sinks to his knees next to Cas. Sam fidgets, rocking his weight between his feet and biting his lip. He wants to stick to the plan but he feels like he's going to burst.

 

“Christ,” Dean mutters, wincing as he tucks his fingertips around the plug nestled in Cas' ass. Come leaks out frothy and glue-thick as Dean pulls it out, tossing it aside carelessly.

 

“You first, Sammy.” Dean presses his thumb alongside Cas' hole, squeezing out a fat pulse of come. It runs down Cas' nuts and pools on the shower floor.

 

“Fuck, Cas,” Sam moans, cupping his hand over his dick. Cas is quivering, his hands shaking as he reaches around. Sam feels frozen, his body locked up as Cas rests his face against the floor and grabs his own ass cheeks, holding himself open for Sam.

 

“Sam, come on,” Dean barks, his face flushed and sweat beading on his brow. It snaps Sam out of his momentary paralysis and Sam nods, not even sure what he's mumbling as he aims his dick and lets go.

 

“Yeah, God, Cas, fuck,” Sam rambles, and _fuck_ , it's almost like coming, unclenching his muscles and letting a stream of piss splash right into Cas' fucked-out hole. Sam's chest goes tight just to flutter open as he moves himself a little, aiming at the thick streaks of come stuck to Cas' nuts. After a second the desperation of his body subsides and he can take in the fucked, pathetic noises Cas is making, just guttural begging sounds that gurgle out where his face is still pressed into the cold shower floor.

 

“That's my boy,” Dean huffs, his voice strained as Sam's stream of piss ebbs. “Piss all the come out of him, just like that.”

 

Cas groans again, digging his fingers into his ass and grunting as he pushes. Sam can see the spent muscles of his hole flex as he forces out a hot stream of Sam's piss, dribbling to the floor and swirling into the rest of the mess beneath him.

 

“Get on your back.” Dean almost knocks Sam over as he knee-walks in between Cas' legs. He guides Cas by the hips, pushing him down and rolling him over. Cas' hair is damp with sweat and _fuck_ , no, it's not sweat, is it? Sam breathes through his mouth, dizzy as he lets his eyes wander from Cas' blissful, wet face down to his spread legs.

 

Impossibly, Cas is hard again. Sam's dick throbs a little just thinking about it, and then Dean points his dick over Cas' red-hard cock and Sam just groans.

 

“Want me to piss all over your cock, Cas?” Dean's voice is so raspy Sam feels it against him, scratching him all over and making him brace a hand against the wall to make sure he doesn't fall.

 

“That's right, that's what you're made for, isn't it?” Dean grits his teeth and makes a rough, strangled noise as he lets out a stream of piss right onto Cas' dick. “Take my cock,” Dean growls, grabbing roughly under Cas' knee and pushing his leg up. “Take my come,” Dean's piss splashes over Cas' hole, close enough that it disappears inside him while Sam's head spins. “Take my fucking piss if I want you to, won't you?”

 

Dean presses his cockhead flush with Cas' hole, emptying himself inside Cas. Sam's not really sure when he wound up on his hands and knees, but he's definitely safer there than standing up.

 

“Dirty boy,” Dean says fondly, his voice more relaxed as he finishes. He takes a heaving breath and angles his hips back, pushing Cas' legs open to watch as a steady stream of piss leaks out of his hole. Cas mewls and works his lips, nothing meaningful coming out.

 

“Christ, you'd probably lick it out of your own asshole if you could.”

 

“ _Dean_.” Cas' eyes snap open, feral and desperate as his hand hovers over his cock.

 

“Gets your fucking dick hard, doesn't it, baby?” Dean bares his teeth as he shakes himself off, splashing a few drops onto Cas' shaking thighs. Cas' eyes are wide like he can't remember how to grab his own dick, so Dean does it for him.

 

“Yeah, come on, Cas, do it.” Dean grins, his head tilted at that cocky angle as he starts to stroke Cas' cock. He's always rougher with Cas, working him hard and fast while Cas moans for it.

 

“Come all over yourself, lying on the fucking floor soaked in your brothers' piss.” Dean's mouth is a thing of beauty when he gets going and Cas is so close, Sam can tell by the way his nose scrunches up a little and his eyes blur out of focus. He looks up at Sam, lips trembling as he bucks up into Dean's hand. Sam nods at him, knowing what Cas needs. He slips his thumb between Cas' lips and groans as Cas sucks greedily. Sam's thumb is wet from the floor and Cas' eyes roll back in his head.

 

“Fuck, we should just leave you like this, just piss in you whenever we fucking feel like it, fuck you dirty and piss you clean again.”

 

Cas' mouth goes slack around Sam's thumb as he comes, not that he's got much left in him at this point. A few thin lines pool on his stomach, mixing with the other wetness slicking his skin. Dean lets Cas' soft cock fold against his thigh as he splays his hand over Cas' stomach and presses.

 

“Dean, please,” Cas whines, voice that completely Cas mix of reedy-high and scratchy. Dean massages Cas' belly again and Sam winces in sympathy. Cas is still holding it by some miracle. He can always hold out the longest of the three of them.

 

“Almost,” Dean nods, catching his lip between his teeth and Sam glances down. Dean's fucking hard again, blood-red cock nudging against Cas' piss-soaked hole. Sam groans, head swimming with the dank, nasty-hot smell of it and the whine pouring out of Cas' throat.

 

Dean slides in easy, hiking Cas' hips up until he's half in Dean's lap. Dean wipes a hand over his forehead before grabbing Cas' limp dick and angling it.

 

“You're gonna piss all over yourself while I fuck you.” Dean curls his back and nods, his eyes wide and his lips swollen red and Sam's half-way to hard again himself. Cas closes his eyes, head lolling back as his whole body goes slack and he lets go.

 

Sam has pretty much accepted that he's fucked for any normal sexual experiences. Fucking both your brothers when you're thirteen will pretty much do that to you, and maybe Sam should feel sort of bad about that but right now he just feels sorry for everyone else. Watching Cas piss on his own face while Dean circles his hips in those little pumps that Sam knows are lighting Cas up on the inside, Sam feels drunk on his own life.

 

“Look at him, Sammy,” Dean purrs, his stomach flexing as he starts to fuck Cas a little faster. Cas moans as his dick jumps, splashing a steady stream of piss onto his neck. Each thrust of Dean's hips makes little droplets fly onto his face. He's smiling and it's so fucking pretty Sam feels hot all over.

 

“You look so fucking hot, Cas,” Sam whispers, his voice shaky. Dean lets out a long, contented groan as Cas' stream tapers off.

 

“Hey, Sammy,” Dean says, trying to sound conversational because he's still a smartass even when his balls are smacking against Cas' piss-wet body. “You drank a lot of water, huh?”

 

“Yeah.” Sam's hand reflexively goes to his dick.

 

“Bet you could go again.” Dean punctuates the last two words with rough jabs of his hips, making Cas shake. Cas blinks his eyes open and looks up at Sam through wet lashes.

 

“You should piss on his hole while I fuck it.” Dean makes it sound like the most mundane suggestion and sometimes Sam hates him for being able to keep his cool all the fucking time.

 

“I, _fuck_ ,” Sam gives in, because he does have to piss again and because Jesus fucking Christ. The face Cas makes as Sam rears up onto his knees and points his half-hard dick is so fucking desperate Sam considers holding it just so he can stuff his dick into Cas' mouth and come again.

 

“Sam,” Cas moans, nodding as much as he can while Dean pounds into him. Cas reaches down, his hand shaking as he slides his palm over his spent dick and his tight balls, moving them to the side. Sam swallows and spreads his legs a little wider, making sure the angle's right as he lets it out.

 

“Feel that, Cas?” Dean throws his head back as the warm stream hits the base of his cock, pulling out all the way so Sam can see drops of his own piss rolling down Dean's dick. Sam tilts his hips enough to land a solid hit into the pink gape of Cas' hole.

 

“Gonna fuck Sammy's piss inside you, fill you up so good.” Dean sinks back in, his hands digging into Cas' hips. Cas cries out, and it sounds so fucking wrecked Sam would worry if Cas weren't grinning like he'd lost his mind. Sam smiles, his head light as he empties his bladder onto Dean's slick, fucked-red cock, just to watch it disappear into Cas' abused hole.

 

“God,” and it's all Dean can get out before he comes, the cords on his neck standing out and his arms shaking. His face is beet-red and Sam watches him, loves the way Dean loses some of his bravado when he comes apart like this. Dean shudders and Sam can't stop himself from leaning in to kiss him, to lick the sweat-salt from his lips and feel the thundering pound of his heartbeat where he touches Dean's neck. Dean sighs, soft and sweet for all the nastiness and this is when he's the best.

 

If Sam could think it through, he'd probably stop himself from pulling off Dean's mouth to turn down to Cas' sloppy-wet grin, but Sam doesn't give a flying fuck about anything but kissing Cas right now, kissing his other brother's smiling, sated mouth, no matter what he tastes like. Cas makes a sharp noise of surprise and Sam just kisses him deeper, running his hand into Cas' wet hair and licking into his hot mouth. It's sort of gross but maybe that's what makes it so good, that they're all disgusting together so it'll always be just them. They're ruined for anyone else and Sam rests his forehead against Cas', just breathing.

 

Dean settles on his side with a long sigh, pressing himself against Cas and clumsily pawing at Sam's shoulder. Sam follows him down, letting the cold floor seep into his skin and settle him as he kisses along Cas' neck. Dean does the same on the other side, running his hand over Cas' stomach and tracing small patterns across Cas' chest. Cas feels tense between them, a little shaky and sometimes Cas gets like this. Sam catches Dean's eye and they both know what to do.

 

Dean sits them both up while Sam heaves himself to his feet. He turns on the big waterfall showerhead and makes sure the water is just this side of too hot, the way Cas likes it. Dean scoots them back until he's leaning against the built-in bench, with Cas resting against his chest. They'd learned a long time ago that Cas can curl up on himself after sex if they don't kiss him back open and keep him there with them.

 

“That was so hot, Cas,” Dean breathes into his ear, letting the water pour down on them. He reaches out for a bottle of shampoo and carefully works it into Cas' hair. Cas scrunches his eyes shut as Dean massages his scalp, working up a lather while Sam settles in front of him.

 

“We love you, Cas.” Sam pours some shampoo into his hand and soaps up his own hair, waiting until he's good and sudsy before nudging the tip of his nose against Cas'.

 

Cas slits his eyes open, meeting Sam's and there he is. Sam smiles, watching Cas' shy grin tug up into a broader smile.

 

“You're a dirty little freak, Cas,” Dean tilts Cas' head back, getting shampoo foam all over his shoulder and he leans down to kiss Cas. “And we never, ever want you to change.”

 

Cas hums and that's enough words for him. He lets Sam and Dean clean him off, wrap him up in the fluffiest bathrobe in near reach and bustle him back to Sam's bed. Their skin is still damp and warm as they pile up, Cas' back pressed to Dean's chest and Sam curls up against his front.

 

“Anybody need water?” Dean asks innocently, while Sam reaches up to smack his shoulder.

 

“Shut up, Dean.” Cas blushes red as he says it and Sam laughs.

 

“So,” Sam says sleepily, nudging his nose into the hollow of Cas' throat. His fingers interlace with Dean's, resting together on the dip of Cas' waist.

 

“What should we try next?”

  

 


End file.
